If the EP thinks you've a high risk wpw, he probably will perform an ablation. If the ablation unsuccessful, I believe he/she will implant a pacemaker to pace out any unwanted rhythms. Sometime the new accessory pathway can manifest. It might not manifest during the EP studies so the EP unable to diagnose properly. You can have one accessory pathway, you can have many accessory pathways as well. You can have a fast response one day and slow response in another days. I think it is the tricky part of wpw. Take care.
I just wanted to add that in re your question as to whether WPW is dangerous or not, the current consensus in most of the medical world seems to be that in patients beyond 25 years of age who have few sypmtoms, who have otherwise structurally normal hearts and who are in generally good health, the risk for serious complications is actually quite low. If you're interested, the Venice meeting of the Heart Rhythm Society in 2007 has a couple of video presentations about what parameters seem to be associated with patients at higher risk (which you can google) and there are several sites on the internet that can give you basic statistics about WPW risks in the general population.
It IS frustrating when different doctors give you different opinions about your condition isn't it?! I have had very symptomatic WPW all my life with frequent episodes and have been told everything from "it's an annoyance, don't worry about it" (from an Electrophysiologist) to "You're playing Russian roulette, this could kill you!" (from a regular cardiologist). It's hard to know what to think sometimes, but if it is any reassurance, let me tell you that I am over 50 years old and have traveled in over 30 countries in the last 30 years WITHOUT any major problems.
But, I DO take some precautions. I wear a medic alert bracelet that provides the WPW diagnosis and found it came in handy in Indonesia, (of all places) where the medics at the airport in Jakarta actually checked the bracelet when I was lying down trying to valsalva my way back into normal sinus rhythm. They took me to the airport clinic, where the doctor checked me out, knew all about WPW and watched me carefully while she let me convert myself back to normal rhythm, which took about 30 mins. Then I went on my way with my trip as planned. I always carry a copy of my EKGs with me that show my regular normal sinus rhythm and my PSVT, along with a note from my doctor describing my condition and clearly identifying the steps to take to treat me, including what drugs are safe and which ones are not. I always travel with someone who knows about my condition who can advocate for me if I need it. I carry not only my prescription medication, but also a slip for a refill of my medication in case I lose my medication. I try to take good care of myself on the trip and avoid known triggers if possible.
I can tell you that I've been in Fiji in the middle of a political upheaval coup d'etat involving men with guns, (when I had lots of episodes of tachycardia!) and I was stuck in Yugoslavia during the outbreak of the civil wars there (more men with guns) when I had absolutely NO episodes of PSVT... So the stress of traveling may bring them on, or it may not... The PSVT symptoms themselves, as well as the worry over the possibility that they might occur, definitely makes the traveling more complicated, but for me it was sooo worth going anyway as I would have hated to miss anything!
Check with a good cardiologist, (preferably an Electrophysiologist who also likes to travel!) and ask what precautions he/she would suggest. See if they will write you a letter to carry. Get a Medic Alert ID if you don't already have one. Also, if you stick to countries with advanced health care (most of Europe, some of Asia, Australia, NZ, Canada, etc.) you will find the health care there is as good as, and often better than, that in the US so if you were to need care, you would be likely to get exactly what you need. When I first started traveling, no one had ever heard of WPW or knew what to do about it, but as that episode in Indonesia (in 1989) taught me, there is much more known about WPW and it's treatment now than ever before.
And lastly, use YOUR best judgment. If you check with your doctor, if you think you will be okay, if you are ready to deal with an episode should you were to have one, and if you think you can still go and enjoy yourself without worrying too much, then I say go and enjoy!!
I'd read a story recently about a professional hockey player that during a team physical was diagnosed with WPW, and the doctors told him that if he hasn't had any symptoms yet, he may never have symptoms and not to worry about it. And this is an athlete that pushes his cardiovascular system to the limit many times a week during the season, treated by the very best doctors money can buy.
Hope that helps.
I think you should be fine on your trip given what you've told us in your post. Still, I also understand WPW responds well (is often cured) to Ablation procedures, so you should give that some consideration. It would be best if you have health insurance, I think the procedure will cost some serious money.